The present invention relates to an improved vehicle mounted device for holding, unthreading and disconnecting drill rods and drill rod sections.
As set forth in U.S. Pat. No. 4,345,493, issued to Charles L. Rassieur on Aug. 14, 1982, it is known to insert connected five and ten-foot drill string sections of a drill rod into a hole several hundred feet deep or more and to disconnect these connected drill rods in ten or twenty foot lengths when withdrawn from the hole with the aid of a rod holding device mounted on a suitable vehicle frame. The rod holding device is provided with clamping jaw means removed from the rod during drilling and which, when not drilling, serves to grip the rod to prevent the rod from moving axially and to inhibit the rod from turning.
In the aforementioned patent, unique structure is provided which allows for ready adjustment to accommodate for misalignment of the vehicle relative the drill string to be held by opposed gripping clamps driven by two hydraulic cylinders. The opposed clamps and hydraulic cylinders are carried on a support which is pivotally mounted on a vehicle. The support further includes a power actuated break-out device for breaking a drill string joint gripped by the clamps.
The present invention not only recognizes the many advantages of this previously disclosed unique structure but further recognizes the importance of employing flush, positive engagement of the jaw means with the drill rod section to allow the drill rod section to be held firmly by the jaws regardless of the incline of the surface on which the vehicle supporting this structure rests. Although it is generally known, as disclosed in U.S. Pat. No. 3,844,547, issued to D. M. Lang et al on Oct. 29, 1974, to individually rotate opposed jaw holding members with rotatable structure located immediately adjacent the opposed jaw members to ensure positive engagement of the jaw members with a pipe section during drill string coupling and uncoupling procedures, and although it is generally known to pivot a structural member about two .axes perpendicular to each other, as disclosed in U.S. Pat. No. 4,725,068, issued to C. D. Taylor et al on Feb. 16, 1985, the present invention recognizes the desirability of ensuring positive engagement of jaw means such as in the unique drill rod holding structure as disclosed in aforementioned U.S. Pat. No. 4,345,493. Further, the present invention recognizes the desirability of rotatably adjusting jaw means simultaneously from a position remote from the jaw means and ideally from a position proximate to the vehicle from which a jaw means support member is cantilevered.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.